Manta Flight Systems wrote:

Boeing seems to think it is a big problem.  I think the safe thing to do is
just use on ply of glass between metal and carbon.  Maybe in most cases the
matrix (the epoxy part of the composite) will prevent the carbon fiber from
making contact with the metal but I would not count on it.  I do not think
using carbon fiber over a control tube with movement in between is good
practice.  Even if the carbon (or fiberglass) does not facilitate a galvanic
reaction I would think the rubbing would promote fretting unless it was well
lubricated.

Mark

I think I missed something. Is it the point to make control tubes out of carbon
fiber? If so it is a good idea but perhaps not just lay-up the carbon over
an aluminum tube. I like the idea of a carbon control tube. Should be very
light weight for a given compressive load.

Paul Lamar

This chain started looking at ways to seal the cold air leakage that the Cruiser
gets
flowing forward from the tail section, and  some one proposed a slip tube thru a
bulkhead formed in place on the tube with a parting compound - I think a rubber
bellows would work - the pressures are probably inches of water and the
loads would be too low to worry about.
If you want to make an epoxy/carbon tube the neat set up would be to use
a braid fiber tube and layup on an old flourescent tube, and break it out
after curing - we did this for the rudder post on the light weight wing
system - except it was wrapped with BID not braid. and even with shrink
tape it was lumpy - Vance

 
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